There has been a strong trend in recent years to attempt to make wheelchairs lighter in weight and more portable. Typically, such chairs may be folded to enable their easy transportation, and the wheelchair frames have been formed from tubular material, and most recently high-strength, lightweight, aircraft-grade aluminum tubing. Fabric seats and backrests are secured to the tubing, and the footrest assemblies which are provided typically are movably and/or detachably mounted to the wheelchair frame. Most usually, the footrest assemblies will pivot from a position in front of the chair to a position beside the chair where they will not interfere with the user's ability to get into and out of the wheelchair.
U.S. Pat. Nos. 2,485,016; 2,601,379 and 4,164,354 disclose foldable wheelchair assemblies which have movable footrest assemblies. In U.S. Pat. No. 2,485,016, the footrest can be moved from a horizontal to a vertical position aligned with one of the side frame assemblies. This allows the user to get in and out of the chair and enables folding of the chair to a relatively compact position. Unfortunately, the frame extensions for the footrest still protrude beyond the front of the chair and this portion of the frame is not detachable from the chair.
In U.S. Pat. No. 2,601,379, the footrest assemblies can be mounted to either of the front frame member or the back frame member. Thus, the footrest assemblies are detachable, but they are not swing-away assemblies.
U.S. Pat. No. 4,164,354 discloses a swing-away footrest assembly which is typical of the construction most frequently used in the industry. This footrest assembly employs a pair of pins which are carried by a mounting bracket that is welded to each of the tubular front frame members of the chair. A bifurcated footrest bracket having openings which receive the pins is mounted over the pins, with the footrest being gravity biased down over the pins for pivotal movement between a position in front of the chair and a position beside the chair.
The approach in U.S. Pat. No. 4,164,354 to providing swing-away footrest assemblies has several disadvantages. First, welding of pin carrying mounting brackets to the front tubular members can be accomplished if the front frame members are made of steel. When high-strength aluminum tubing is used in order to lighten chair weight, however, such welding will reduce the strength of the tubing by about one half. The use of steel front frame members to provide sufficient strength to enable welding results in an increase in a chair weight of at least about five pounds. Second, quadriplegics having limited manual dexterity have considerable problems in connection with aligning the two openings in the footrest bracket with the two pins on the chair frame. This task can be very tedious and difficult for a quadriplegic wheelchair user to perform. Third, such swing-away footrest assemblies often include a latching structure which will latch the footrest in the position in front of the chair which is also very difficult for a quadriplegic to operate. Thus, latching systems which employ one or more buttons that must be pressed in order to release the latch can be very difficult for users having limited manual dexterity.
Another problem which is encountered as the overall weight of a wheelchair decreases is the need to maintain sufficient rigidity in the chair so that the user feels secure in the chair. Thus, swingaway footrest assemblies must be capable of not only being latched in a position in front of the chair, but the assembly is most preferably relatively rigidly coupled to the frame in the latched position. The user may, therefore, support considerable lower body weight on the footrest without having a feeling that the rests will wobble with respect to the frame.
Another significant aspect of the manufacture of lightweight wheelchairs has been the need to reduce the number of components in the chair. Thus, the swing-away footrest assembly and latch assembly preferably should have a minimum number of parts so as to provide the advantages of a swing-away footrest without an undesirable increase in the overall complexity and cost of the chair.